CN110367592B

CN110367592B - Liquid aerosol formulation for electronic smoking article

Info

Publication number: CN110367592B
Application number: CN201910633386.2A
Authority: CN
Inventors: 彼得·利波维奇; 波林·马尔科; 戈尔德·科巴尔; 姆玛亚·K·米什拉; 乔治·D·卡尔赖斯; S·李
Original assignee: Altria Client Services LLC
Current assignee: Altria Client Services LLC
Priority date: 2013-07-19
Filing date: 2014-07-16
Publication date: 2022-12-02
Anticipated expiration: 2034-07-16
Also published as: EP3021699B1; EA033402B1; IL243679A0; ZA201601131B; US20220273020A1; EP3021699A2; CN105530825A; IL243679B; MY179801A; ZA202002712B; WO2015009862A2; AR096975A1; US20150020823A1; US10660365B2; EA201690249A1; WO2015009862A3; US20200245678A1; UA122320C2; CN110367592A; US11337453B2

Abstract

The present invention relates to liquid aerosol formulations, electronic smoking articles, methods of forming aerosols by electronic smoking articles, methods of forming components of electronic smoking articles, and liquid formulations for electronic smoking articles. The liquid aerosol formulation comprises: an aerosol former; water; nicotine bitartrate in an amount sufficient to produce at least 2% nicotine; and an acidic material that coagulates at ambient temperature and has a boiling point of at least 150 ℃, the acidic material comprising one of succinic acid, tartaric acid, sulfuric acid, carbonic acid, malonic acid, tartronic acid, acetic acid, benzoic acid, adipic acid, glutaric acid, pimelic acid, subcombinations thereof, or combinations thereof, in an amount sufficient to provide a pH for the liquid aerosol formulation of between about 4 and about 8; the liquid aerosol formulation forms an aerosol upon heating having a particulate phase comprising protonated nicotine and a gas phase comprising unprotonated nicotine, the gas phase of the aerosol having a nicotine content in the gas phase of equal to or less than about 1% of the total nicotine content.

Description

Liquid aerosol formulation for electronic smoking article

The present application is a divisional application of chinese invention patent with application date 2014 16, application number 201480050829.0, entitled "liquid aerosol formulation for electronic smoking article" filed by the same applicant.

Technical Field

The present invention relates to a liquid aerosol formulation. The invention also relates to an electronic smoking article comprising the liquid aerosol formulation described above. The invention also relates to a method of forming an aerosol by an electronic smoking article. The invention also relates to a method of forming a component of an electronic smoking article. The invention also relates to a liquid formulation for an electronic smoking article.

Background

Lit-end smoking articles produce aerosols known to give adult smokers a pleasant sensory experience, including a low to mild bitter response in the throat and a warming sensation in the chest cavity. Preference levels for bitterness in the throat and warmth sensation in the chest are different in adult cigarette smokers.

Disclosure of Invention

One object of the teachings herein is to achieve an electronic smoking article, such as an electronic cigarette, that can provide adult smokers with a pleasant sensory experience similar to that they enjoy when smoking an end lit cigarette.

Another object of the teachings herein is to implement an electronic smoking article that can provide a sensory experience that includes multiple levels of harshness in the throat and warmth in the chest similar to that experienced by an adult smoker when smoking a lit-end cigarette.

According to a first aspect of the present invention, there is provided a liquid aerosol formulation comprising: an aerosol former; water in an amount of from 0.1% to about 40% by weight based on the weight of the liquid aerosol formulation; nicotine bitartrate in an amount sufficient to produce at least 2% nicotine by weight based on the weight of the liquid aerosol formulation; and an acidic material that is condensable at ambient temperature, the acidic material having a boiling point of at least 150 ℃, the acidic material comprising one of succinic acid, tartaric acid, sulfuric acid, carbonic acid, malonic acid, tartronic acid, acetic acid, benzoic acid, adipic acid, glutaric acid, pimelic acid, subcombinations thereof, or combinations thereof, in an amount sufficient to provide the liquid aerosol formulation with a pH in the range of from about 4 to about 8; wherein the liquid aerosol formulation, when heated, forms an aerosol having a particulate phase and a gas phase, the particulate phase comprising protonated nicotine and the gas phase comprising unprotonated nicotine, the gas phase nicotine in the aerosol being present in an amount equal to or less than about 1% of the total content of nicotine in the aerosol.

Preferably, the liquid aerosol formulation further comprises at least one fragrance in an amount ranging from about 0.2% to about 15% by weight.

Preferably, the aerosol former comprises one of propylene glycol, glycerin, a sub-combination thereof, or a combination thereof.

Preferably, the aerosol former content is in the range from about 40% to about 90% by weight.

Preferably, the liquid aerosol formulation comprises glycerin and propylene glycol in a ratio of about 2:3 or greater.

Preferably, the particulate phase comprises particles ranging in size from about 0.2 microns to about 2 microns.

Preferably, the acidic material is present in an amount ranging from about 0.1% to about 15% by weight.

Preferably, the acidic material comprises one of succinic acid, sulfuric acid, carbonic acid, tartronic acid, acetic acid, benzoic acid, adipic acid, glutaric acid, pimelic acid, subcombinations thereof, or combinations thereof.

Preferably, the acidic substance comprises tartaric acid.

Preferably, the liquid aerosol formulation further comprises ammonia or an ammonia-containing compound in an amount sufficient to lower the pH of the liquid aerosol formulation by about 1 to about 2 pH units.

Preferably, the water content ranges from about 5% to about 40% by weight based on the weight of the liquid aerosol formulation.

Preferably, the water content ranges from about 5% to about 15% by weight based on the weight of the liquid aerosol formulation.

Preferably, the liquid aerosol formulation has a pH in the range of from about 5.5 to about 8.

According to a second aspect of the invention, there is provided an electronic smoking article comprising: a heater; and the liquid aerosol formulation described above; wherein the heater is operative to volatilize the liquid aerosol formulation and form an aerosol.

Preferably, the electronic smoking article further comprises a container containing the liquid aerosol formulation; wherein the heater comprises a capillary tube in fluid communication with the reservoir.

Preferably, the container comprises a valve at an outlet of the container.

Preferably, the container is compressible.

Preferably, the electronic smoking article further comprises: a filamentous core; and a container; wherein the heater is a heating coil in communication with the filamentary wick and the filamentary wick draws the liquid aerosol formulation from the container by capillary action.

Preferably, the electronic smoking article further comprises: an outer tube extending in a longitudinal direction; and an inner tube located within the outer tube; wherein the heating coil is located in the inner tube, the filamentary wick is in communication with the container and surrounded by the heating coil such that the filamentary wick can deliver the liquid aerosol formulation to the heating coil, which heats the liquid aerosol formulation to a temperature sufficient to vaporize the liquid aerosol formulation and form an aerosol.

Preferably, the acidic substance comprises tartaric acid.

According to a third aspect of the present invention, there is provided a method of forming an aerosol by an electronic smoking article, the method comprising heating a liquid aerosol formulation to a temperature sufficient to form an aerosol, the liquid aerosol formulation comprising an aerosol former; water in an amount of from 0.1% to about 40% by weight based on the weight of the liquid aerosol formulation; nicotine bitartrate in an amount sufficient to produce at least 2% nicotine by weight based on the weight of the liquid aerosol formulation; and an acidic material in an amount sufficient to provide the liquid aerosol formulation with a pH in a range from about 4 to about 8, the acidic material being condensable at ambient temperature, the acidic material having a boiling point of at least 150 ℃, the acidic material comprising one of succinic acid, tartaric acid, sulfuric acid, carbonic acid, malonic acid, tartronic acid, acetic acid, benzoic acid, adipic acid, glutaric acid, pimelic acid, subcombinations thereof, or combinations thereof; wherein, during operation of the electronic smoking article, the liquid aerosol formulation is capable of forming, when heated, an aerosol having a particulate phase and a gas phase, the gas phase of the aerosol having a nicotine content equal to or less than about 1% of the total nicotine content of the aerosol.

Preferably, the acidic material comprises tartaric acid in an amount ranging from about 0.1% to about 15% by weight based on the weight of the liquid aerosol formulation.

Preferably, the liquid aerosol formulation further comprises ammonia or an ammonia-containing compound in an amount sufficient to reduce the pH of the liquid aerosol formulation by about 1 to about 2 pH units.

According to a fourth aspect of the present invention, there is provided a method of forming a component of an electronic smoking article, the method comprising: preparing a liquid aerosol formulation by mixing an aerosol former in an amount of at least about 50% by weight based on the weight of the liquid aerosol formulation, water in an amount of 0.1% to about 40%, and an acidic material that is condensable at ambient temperature, the acidic material having a boiling point of at least 150 ℃, the acidic material in an amount sufficient to provide the liquid aerosol formulation with a pH in a range from about 4 to about 8, the acidic material comprising one of succinic acid, tartaric acid, sulfuric acid, carbonic acid, malonic acid, tartronic acid, acetic acid, benzoic acid, adipic acid, glutaric acid, pimelic acid, subcombinations thereof, or combinations thereof, the amount of the nicotine bitartrate added to the liquid aerosol formulation by weight based on the weight of the liquid aerosol formulation being sufficient to produce at least 2% nicotine, the content of gas phase nicotine in the aerosol being equal to or less than about 1% of the total content of nicotine in the aerosol; and a container for filling a component of an electronic smoking article with the liquid aerosol formulation.

Preferably, the acidic substance comprises tartaric acid.

According to a fifth aspect of the present invention, there is provided a liquid formulation for an electronic smoking article, the liquid formulation comprising: an aerosol former; water in an amount of from 0.1% to about 40% by weight based on the weight of the liquid formulation; a nicotine salt in an amount sufficient to produce at least 2% nicotine by weight based on the weight of the liquid formulation; and benzoic acid in an amount ranging from about 2.0% to about 8.0% by weight.

Preferably, the amount of nicotine salt is in the range of from about 2% to about 6% by weight, the benzoic acid is present in an amount sufficient to provide the liquid formulation with a pH value in the range of from about 4 to about 8, the liquid aerosol formulation, when heated, forms an aerosol having a particulate phase comprising protonated nicotine and a gas phase comprising unprotonated nicotine, the gas phase nicotine in the aerosol being present in an amount equal to or less than about 1% of the total content of nicotine in the aerosol.

Preferably, the aerosol former comprises glycerol and propylene glycol.

Preferably, the nicotine salt comprises nicotine bitartrate.

Preferably, the aerosol former comprises glycerol and propylene glycol in a ratio of about 2:3.

In one embodiment, a liquid aerosol formulation for use in an electronic smoking article having a heater operating temperature is presented. The liquid aerosol formulation includes an aerosol former; water in an amount of from 0% to about 40% by weight based on the weight of the liquid aerosol formulation; nicotine in an amount of at least about 2% by weight based on the weight of the liquid aerosol formulation; and an acidic material having a melting point and/or boiling point of at least about 150 ℃ and such that the acidic material is volatile at the heater temperature and condensable at ambient temperature. The acidic material is present in an amount sufficient to provide the liquid aerosol formulation with a pH in the range of from about 4 to about 8. The liquid aerosol formulation forms an aerosol having a particulate phase and a gas phase when heated during operation of the electronic smoking article. The particulate phase comprises protonated nicotine and the gas phase comprises unprotonated nicotine. The aerosol has a gas phase nicotine content less than about 1% of a total nicotine content of the aerosol.

The liquid aerosol formulation may further include at least one flavorant in an amount ranging from about 0.2% to about 15% by weight. Additionally, the aerosol former is selected from the group consisting of propylene glycol, glycerin, and combinations thereof. The amount of aerosol former ranges from about 40% by weight to about 90% by weight. The acidic material preferably has a boiling point in the range of from about 150 ℃ to about 250 ℃, or the acidic material preferably has a melting point in the range of from about 150 ℃ to about 250 ℃. In one embodiment, the acidic material has a melting point and/or boiling point of from about 150 ℃ to about 300 ℃. In a preferred embodiment, the liquid formulation comprises glycerin and propylene glycol in a ratio of about 2:3 or greater. In addition, the amount of nicotine included ranges from about 2% by weight to about 10% by weight. The particulate phase includes particles ranging in size from about 0.2 microns to about 2 microns. The amount of the acidic substance included ranges from about 0.1% by weight to about 15% by weight. The amount of water included ranges from about 5% by weight to about 40% by weight based on the weight of the liquid aerosol formulation, or from about 5% to about 15% by weight based on the weight of the liquid aerosol formulation. In one embodiment, the liquid aerosol formulation has a pH in the range of from about 5.5 to about 8.

In one embodiment, the liquid aerosol formulation further comprises ammonia or an ammonia-containing compound in an amount sufficient to lower the pH of the liquid aerosol formulation by about 1 to about 2 pH units.

The acidic material is selected from the group consisting of succinic acid, tartaric acid, sulfuric acid, carbonic acid, malonic acid, tartronic acid, levulinic acid, acetic acid, benzoic acid, adipic acid, glutaric acid, pimelic acid, and combinations thereof. In a preferred embodiment, the acidic substance comprises tartaric acid. In another preferred embodiment, at least a portion of the acidic material and at least a portion of the nicotine are from a nicotine acid salt. Also preferably, the nicotine acid salt comprises nicotine bitartrate.

In another embodiment, an electronic smoking article is provided that is operable to produce an aerosol that substantially simulates the sensory experience of a lit-end cigarette. An electronic smoking article includes a heater, and a liquid aerosol formulation. The heater is operative to volatilize the liquid aerosol formulation and form an aerosol. The liquid aerosol formulation comprises an aerosol former; water in an amount from 0% to about 40% by weight based on the weight of the liquid aerosol formulation; nicotine in an amount of at least about 2% by weight based on the weight of the liquid aerosol formulation; and an acidic material in an amount sufficient to provide the liquid aerosol formulation with a pH in the range of from about 4 to about 8. The liquid aerosol formulation is capable of forming an aerosol having a particulate phase and a gas phase when heated by the heater. The particulate phase comprises protonated nicotine and the gas phase comprises unprotonated nicotine. The aerosol has a large amount of protonated nicotine and a small amount of unprotonated nicotine. The sensory experience included a feeling of chest warmth and mild throat harshness during suctioning.

In one embodiment, the heater comprises a capillary tube in communication with a reservoir containing the liquid aerosol formulation. The container is squeeze-type and includes a mechanically or electrically operated valve at the outlet of the container. The container is compressible so that the liquid material can be manually pumped to the capillary.

In one embodiment, the heater is a heating coil in communication with a filamentary wick that draws liquid from the container by capillary action. The electronic smoking article further includes an outer tube extending in the longitudinal direction, an inner tube located within the outer tube, and a container including an outer annular region located between the outer tube and the inner tube. A heater coil is positioned within the inner tube, and a filamentary wick is in communication with the container and surrounded by the heater coil such that the wick is capable of delivering the liquid aerosol formulation to the heater coil and the heater coil is capable of heating the liquid aerosol formulation to a temperature sufficient to vaporize the liquid aerosol formulation and form an aerosol.

In one embodiment, a method of simulating a sensory experience of a smoking lit-end cigarette includes heating a liquid aerosol formulation to form an aerosol. The liquid aerosol formulation comprises an aerosol former; water in an amount from 0% by weight to about 40% by weight, based on the weight of the liquid aerosol formulation; nicotine in an amount of about 2% or more by weight based on the weight of the liquid aerosol formulation; and an acidic material in an amount sufficient to provide the liquid aerosol formulation with a pH in the range of from about 4 to about 8. Aerosols have a particulate phase and a gas phase. The particulate phase comprises protonated nicotine and the gas phase comprises unprotonated nicotine. The unprotonated nicotine is preferably less than about 1% of the total nicotine content of the aerosol. The sensory experience includes a feeling of chest warmth and moderate throat harshness during a puff. In addition, the acidic substance has a melting point and/or boiling point of at least about 150 ℃, such that the acidic substance is capable of volatilizing at the heater temperature and condensing at ambient temperature.

In another embodiment, a method of forming an aerosol by an electronic smoking article includes heating a liquid aerosol formulation to a temperature sufficient to form an aerosol. The liquid aerosol formulation comprises an aerosol former; water in an amount from 0% by weight to about 40% by weight, based on the weight of the liquid aerosol formulation; nicotine in an amount of at least about 2% by weight based on the weight of the liquid aerosol formulation; and an acidic material in an amount sufficient to provide the liquid aerosol formulation with a pH in the range of from about 4 to about 8. The acid acts on the aerosol to reduce the degree of throat harshness experienced by the smoker as compared to an aerosol formed upon operation of the electronic smoking article that is free of the acid.

In one embodiment, the acidic material comprises tartaric acid in an amount ranging from about 0.1% by weight to about 15% by weight, based on the weight of the liquid aerosol formulation. Additionally, the liquid aerosol formulation may further comprise ammonia or an ammonia-containing compound in an amount sufficient to lower the pH of the final liquid aerosol formulation by about 1 to about 2 pH units.

In yet another embodiment, a method of forming a component of an electronic smoking article includes preparing a liquid aerosol formulation by mixing an aerosol former in an amount of at least about 50% by weight based on the weight of the liquid aerosol formulation with water in an amount of about 5% by weight to about 40% by weight based on the weight of the liquid aerosol formulation; adding nicotine bitartrate in an amount sufficient to establish a nicotine content of the liquid aerosol formulation of at least about 2% by weight, and filling a container of a component of the electronic smoking article with the liquid aerosol formulation.

In another embodiment, an aerosol is made by heating a liquid aerosol formulation in an electronic smoking article. The liquid aerosol formulation includes nicotine and an acidic material, the nicotine being in an amount of at least about 2% by weight based on the weight of the liquid aerosol formulation. The nicotine is present in an amount sufficient to produce a sensation of chest warmth associated with smoking a lit-end cigarette. The aerosol has a gas phase nicotine content of the aerosol that is less than 1% of a total nicotine content of the aerosol. The acid acts on the aerosol to reduce the degree of throat harshness experienced by the smoker as compared to an aerosol formed upon operation of the electronic smoking article that is free of the acid.

Drawings

Figure 1 is a side view of an electronic smoking article constructed in accordance with one embodiment.

Figure 2 is a cross-sectional view of an electronic smoking article according to one embodiment.

Figure 3 is a cross-sectional view of another embodiment of an electronic smoking article according to one embodiment.

Figure 4 is a cross-sectional view of an electronic smoking article according to one embodiment.

Figure 5 is a schematic diagram showing the gas phase nicotine content per puff of an electronic smoking article comprising a liquid aerosol formulation that does not contain at least one acidic substance compared to the gas phase nicotine content per puff of an electronic smoking article comprising a liquid aerosol formulation that contains at least one acidic substance described herein.

Detailed Description

In one embodiment, an electronic smoking article includes a liquid supply (container) containing a liquid aerosol formulation. The liquid aerosol formulation is delivered to a heater where it is heated and volatilized. The term "electronic smoking article" as used herein includes all types of electronic smoking articles, regardless of form, size or shape, including electronic cigarettes, electronic cigars, electronic pipes, electronic hookahs, and the like. Additionally, the liquid aerosol formulation may contain tobacco flavors or substitutes, or mixedly include other suitable flavors.

In a preferred embodiment, the liquid aerosol formulation comprises (includes) an acidic substance (by "acidic substance" as used herein is meant one or more acidic substances) which protonates substantially all nicotine molecules in the liquid formulation, such that upon heating of the liquid aerosol formulation in an electronic smoking article, an aerosol is produced having a large amount of protonated nicotine and a small amount of unprotonated nicotine, whereby only a small portion of all volatilized (evaporated) nicotine remains in the gas phase of the aerosol.

Preferably, the aerosol produced from the liquid aerosol formulation comprises unprotonated nicotine in an amount ranging from about 0.1% to about 1.0% by weight based on the total nicotine content in the aerosol, more preferably from about 0.1% to about 0.5% by weight based on the total nicotine content in the aerosol. Since most of the nicotine in the aerosol is protonated, the aerosol helps to produce a low to mild bitter sensory response in the throat, even at higher nicotine levels in liquid aerosol formulations. Most of the foregoing can occur because the protonated nicotine is charged and does not enter or remain in the gas phase of the aerosol, but rather is in the particulate phase of the aerosol.

Preferably, the acidic substance: (a) Sufficiently thermally stable to withstand a heating cycle of the electronic smoking article such that at least a majority of the acidic species can enter the gas vapor phase as an acidic species; (b) volatilizing at a heater temperature; and (c) condensing at ambient temperature. In a preferred embodiment, the acidic material has a melting and/or boiling point of at least about 150 ℃ and is present in the liquid aerosol formulation in an amount sufficient to adjust the pH of the liquid aerosol formulation to from about 4 to about 8, more preferably from about 5.5 to about 8.

As shown in fig. 1, the liquid aerosol formulations disclosed herein form an aerosol when vaporized within an electronic smoking article. The electronic smoking article 60 includes a replaceable cartridge (or first part) 70 and a reusable securing part (or second part) 72 that are joined together at a threaded joint 74 or by other convenient means (e.g., a snug fit, snap fit, detents, clips, and/or hooks).

As shown in fig. 3, the first portion 70 may contain a mouthpiece end insert 20, a capillary aerosol generator comprising a capillary element (capillary tube) 18, a heater 19 for heating at least a portion of the capillary element 18, a reservoir 14, and optionally a valve 40. Alternatively, as shown in FIG. 4, the first portion 70 may contain a mouth end insert 20, a heater 319, a flexible filamentary wick 328, and a reservoir 314, as will be described in greater detail below.

The second portion 72 may contain a power source 12 (as shown in fig. 2, 3, and 4), a control circuit 11, and optionally a puff sensor 16 (as shown in fig. 3 and 4). When the threaded portion 74 of the second portion 72 is not connected to the first portion 70, it is connected to a battery charger to charge the battery.

As shown in fig. 2, the electronic smoking article 60 can further include an intermediate portion (third portion) 73, which can contain the reservoir 14, the heater 19, and the valve 40. The intermediate portion 73 may be adapted to cooperate with a nipple 74' at the upstream end of the first portion 70 and a nipple 74 at the downstream end of the second portion 72. In this embodiment, the first portion 70 contains the mouth end insert 20, while the second portion 72 contains the power source 12 and control circuitry.

Preferably, the first, second and optional

third portions

70, 72, 73 comprise an outer cylindrical housing 22, the outer cylindrical housing 22 extending in a longitudinal direction along the length of the electronic smoking article 60. Additionally, in one embodiment, the intermediate portion 73 is disposable and the first portion 70 and/or the second portion 72 are reusable. In another embodiment, the first portion 70 can also be replaceable to avoid the need to clean the capillary element 18 and/or the heater 19. The

portions

70, 72, 73 may be connected by a threaded connection whereby the intermediate portion 73 may be replaced when the liquid aerosol formulation in the container 14 is used up.

It is contemplated that the first portion 70 and the second portion 72 may be unitary and not require threaded connections.

As shown in fig. 2, the outer cylindrical shell 22 may include a cutout or depression 102 that allows a smoker to manually apply pressure to the container 14. Preferably, the outer cylindrical shell 22 is flexible and/or compressible along its length and covers the container 14 completely or partially. The cutout or depression 102 may extend partially around the circumference of the cylindrical outer shell 22. In addition, the reservoir 14 is compressible so that liquid can be pumped from the reservoir 14 to the capillary 18 when pressure is applied to the reservoir. A pressure activated switch 44 may be provided below the container 14. When pressure is applied to the container 14 to pump the liquid, the switch is also depressed and the heater 19 is activated. The heater 19 may be part of the capillary element 18. By applying manual pressure to the pressure switch, the power source 12 is activated and current passes through the electrical contacts to heat the liquid in the capillary element 18 in order to volatilize the liquid.

In the embodiment of fig. 2, the container 14 is a tubular, elongated body formed of a resilient material so as to be able to flex and/or be compressed when squeezed. Preferably, the elastic material may be selected from the group consisting of silicone rubber, plastic, rubber, latex, and combinations thereof.

Preferably, the compressible reservoir 14 has an outlet 17, the outlet 17 being in fluid communication with the capillary element 18, such that the reservoir 14, when squeezed, can deliver a quantity of liquid material to the capillary element 18. While delivering the liquid to the capillary element, the power source 12 is activated based on the application of manual pressure to the pressure switch, and the capillary element 18 is heated to form a heated portion in which the liquid material inside volatilizes. The volatilized material expands, mixes with air, and forms an aerosol upon exiting the heated capillary element 18.

Preferably, the container 14 extends longitudinally within the cylindrical outer housing 22 of the first portion 70 (as shown in fig. 3 and 4) or the intermediate portion 73 (as shown in fig. 2). In addition, the container 14 contains a liquid aerosol formulation that volatilizes when heated and forms an aerosol when discharged from the capillary tube 18.

In the embodiment shown in fig. 2 and 3, the capillary wick 18 includes an inlet end 62 in fluid communication with the outlet 17 of the container 14, and an outlet end 63 operable to expel volatilized liquid material from the capillary element 18. In a preferred embodiment, as shown in fig. 2 and 3, the container 14 may include a valve 40.

As shown in FIG. 2, the valve 40 may be a check valve that is operable to retain the liquid material within the container, yet will open when the container 14 is squeezed and pressure is applied. Preferably, upon reaching a critical, minimum pressure, the check valve 40 will open to avoid accidental discharge of liquid material from the container 14 or accidental activation of the heater 19. Preferably, the threshold pressure required to open the check valve 40 is substantially equal to or slightly less than the pressure required to depress the pressure switch 44 to activate the heater 19. Preferably, the pressure required to press the pressure switch 44 is high enough to avoid accidental heating. This arrangement can avoid activating the heater 19 when liquid is not being pumped through the capillary element.

Advantageously, if pumped manually, the use of the check valve 40 helps to limit the amount of liquid that is withdrawn from the capillary upon release of the pressure applied to the container 14 (and/or the switch 44) so as to avoid drawing air into the container 14. The presence of air can reduce the pumping performance of the container 14.

Upon release of the pressure applied to the container 14, the valve 40 closes. Heated capillary element 18 will cause liquid held downstream of valve 40 to flow out.

Optionally, a critical flow orifice 41 is provided downstream of the check valve 40 to determine the maximum flow rate of liquid to the capillary element 18.

In other embodiments, as shown in fig. 3, the valve 40 may be a two-way valve and the container 14 may be squeezed. For example, the container 14 may be squeezed using a pressure member 405, the pressure member 405 applying a constant pressure to the container 14. For example, an internal or external spring and a plate may be used to apply pressure to container 14, with the plate constantly applying pressure to container 14. Alternatively, the container 14 may be compressed and located between two plates connected by a spring, or the container 14 may be compressed and located between an outer housing and a plate connected by a spring, so that the plate can apply pressure to the container 14.

Preferably, the capillary element 18 of fig. 2 and 3 has an inner diameter of from 0.01 mm to 10 mm, preferably from 0.05 mm to 1 mm, and more preferably from 0.05 mm to 0.4 mm. A capillary element with a smaller diameter will provide more efficient heat transfer to the fluid because the shorter the distance to the center of the fluid, the less energy and time is required to evaporate the liquid.

Also preferably, the capillary element 18 may have a length of from about 5 mm to about 72 mm, more preferably from about 10 mm to about 60 mm, or from about 20 mm to about 50 mm. In one embodiment, the capillary element 18 is substantially straight. In further embodiments, the capillary element 18 is helical, and/or includes one or more bends therein to save space and/or accommodate a long capillary element.

In these embodiments, the capillary element 18 is formed from a conductive material and thus acts itself as a heater 19 by passing an electric current through the capillary element. The capillary element 18 can be any electrically conductive material that can be resistively heated while maintaining the necessary structural integrity at the operating temperatures experienced by the capillary element 18, and that does not react with the liquid material. Suitable materials for forming capillary 18 are selected from the group consisting of stainless steel, copper alloys, porous ceramic materials coated with film resistive materials, commercially available from Special Metals, inc

(which is a nickel-chromium alloy),

(which is also a nickel-chromium alloy) and combinations thereof.

In one embodiment, the capillary element 18 is a stainless steel capillary element 18 that can act as a heater 19 by virtue of an electrically conductive element 26 connected thereto, which acts as a conduit for direct or alternating current along the length of the capillary element 18. Thereby, the capillary element 18 of stainless steel is heated by resistance heating. The stainless steel capillary element 18 preferably has an annular cross-section and may be formed from tubing suitable for use as an injection needle for various meters. For example, capillary 18 may include a 32 gauge needle having an inner diameter of 0.11 millimeters and a 26 gauge needle having an inner diameter of 0.26 millimeters.

In another embodiment, the capillary element 18 may be a non-metallic tube, such as a glass tube. In this embodiment, the heater 19 is formed of a conductive material capable of resistance heating, such as stainless steel, nichrome or platinum wire, disposed along the glass tube. When heated by a heater disposed along the glass tube, the liquid material within the capillary element 18 may be heated to a temperature sufficient to at least partially volatilize the liquid material within the capillary element 18.

Preferably, at least two conductive elements 26 are bonded to metal capillary 18. In a preferred embodiment, at least two conductive elements 26 are soldered to capillary member 18. Preferably, as shown in fig. 2 and 3, one conductive member 26 is welded to the first, upstream portion 101 of the capillary 18, and a second conductive member 26 is welded to the downstream, end portion 107 of the capillary 18.

In use, once the capillary element 18 of fig. 2 and 3 is heated, the liquid material contained in the heated portion of the capillary element 18 volatilizes and is discharged out of the outlet 63, where it expands and mixes with air and forms an aerosol in the mixing chamber 240.

As mentioned above, the liquid aerosol formulation may also be used in an electronic smoking device comprising a heater 319 and a filamentary wick 328 as shown in figure 4. The first portion 70 includes an outer tube (or housing) 22 extending in a longitudinal direction and an inner tube (or chimney) 362 coaxially disposed within the outer tube 22. Preferably, the nose 361 of the upstream gasket (or seal) 320 fits within the upstream end 365 of the inner tube 362, while the outer edge 367 of the gasket 320 in combination with the inner surface 397 of the outer shell 22 provides a fluid-tight seal. The upstream gasket 320 also includes a central longitudinal air passage 315, the passage 315 opening into the interior of the inner tube 362 that defines the central passage 321. The transverse passage 333 at the upstream portion of the gasket 320 intersects and communicates with the central longitudinal air passage 315 of the gasket 320. The channel 333 ensures that the centrally located longitudinal air passage 315 communicates with the space 335 defined between the washer 320 and the threaded connection 74.

Preferably, the nose 393 of the downstream gasket 310 fits into the downstream end portion 381 of the inner tube 362. The outer extension 382 of the gasket 310 provides a generally fluid-tight seal in conjunction with the inner surface 397 of the outer housing 22. The downstream gasket 310 includes a central passage 384 disposed between the central passage 321 of the inner tube 362 and the nozzle end insert 20.

In this embodiment, the container 314 is contained within an annular region between the inner tube 362 and the outer casing 22 and between the upstream gasket 320 and the downstream gasket 310. Thus, the container 314 at least partially surrounds the central air passage 321. The container 314 contains a liquid material and optionally a liquid storage medium (not shown) operable to store the liquid material therein.

The inner tube 362 has a central air passage 321 extending therethrough, the central air passage 321 receiving the heater 319. The heater 319 is in contact with a filamentary wick 328, which wick 328 preferably extends between opposite portions of the container 314 to facilitate the transfer of the liquid aerosol formulation from the container 314 to the heater 319.

Preferably, the electronic smoking article 60 of the various embodiments described herein further comprises at least one air inlet 440. As shown in fig. 4, at least one air inlet 440 may be located upstream of the heater 319.

In the embodiment shown in fig. 2 and 3, the at least one air inlet 440 is preferably disposed downstream of the capillary element 18 in order to minimize air draw along the capillary element and thereby avoid cooling of the capillary element 18 during the heating cycle.

In embodiments, the at least one air inlet 440 includes one or two air inlets. Alternatively, there may be three, four, five or more air inlets. Varying the size and number of the air inlets 440 may also help to establish the resistance to draw of the electronic smoking article 60.

The power source 12 of various embodiments may include a battery disposed within the electronic smoking article 60. The power source 12 is operable to apply a voltage across the heater 19 (shown in fig. 2 and 3) connected to the capillary element 18, or across the heater 319 (shown in fig. 4) connected to the filamentary wick 328. The

heater

19, 319 thereby volatilizes the liquid material according to the power cycle for any predetermined period of time, for example for a period of 2 to 10 seconds.

Preferably, the electrical contact or electrical connection between the

heater

19, 319 and the conductive member 26 is very conductive and heat resistant, while the electrical resistance of the

heater

19, 319 is very large, so that heat is generated mainly along the heater 19 and not at the contact.

The battery may be a lithium ion battery or one of its variants, for example a lithium ion polymer battery. Alternatively, the battery may be a nickel-hydrogen battery, a nickel-cadmium battery, a lithium-manganese battery, a lithium-cobalt battery, or a fuel cell. In this case, preferably, the electronic smoking article 60 can be used by the smoker until the energy in the power source is depleted. Alternatively, the power source 12 may be rechargeable and include circuitry that allows the battery to be charged by an external charging device. In this case, the circuitry may provide energy for a predetermined number of pumping actions, preferably upon completion of charging, after which the circuitry must be reconnected to the external charging device.

Preferably, the electronic smoking article 60 of various embodiments further comprises a control circuit 11 (as shown in fig. 2, 3, and 4), and the control circuit 11 may be on a printed circuit board. The control circuit 11 may also include a heater activation light 27 operable to emit light when the

heater

19, 319 is activated. Preferably, the heater activation light 27 comprises at least one LED and is located at the upstream end 28 of the electronic smoking article 60 (as shown in fig. 1), such that the heater activation light 27 illuminates the end caps during smoking to present a coal-fired appearance. In addition, the heater activation light 27 may be provided to be visible to the smoker. In addition, the heater activation light 27 may be used for smoking article system diagnostics. The light 27 may also be arranged so that the smoker can activate and/or deactivate the light 27 when desired, so that the light 27 can be deactivated during smoking, if desired.

The time for powering the heater 19 can be preset according to the amount of liquid to be evaporated. The control circuit 11 is programmable and may comprise an Application Specific Integrated Circuit (ASIC). In other embodiments, the control circuit 11 may include a microprocessor programmed to perform functions such as heating the capillary element and/or operating the valve.

As shown in fig. 2, 3 and 4, the electronic smoking article 60 further comprises a mouth end insert 20, the mouth end insert 20 having at least two off-axis, preferably diverging, outlets 21. Preferably, the nozzle end insert 20 comprises at least two diverging outlets 21. (e.g., 3, 4, 5, or preferably 6 to 8 outlets, or more). Preferably, the outlet 21 of the mouth end insert 20 is located at the end of the off-axis channel 23 and is skewed outwardly (i.e., divergent) relative to the longitudinal direction of the electronic smoking article 60. The term "off-axis" as used herein refers to an angle relative to a longitudinal direction of the electronic smoking article. It is also preferred that the mouth end insert (or flow director) 20 includes outlets evenly distributed around the mouth end insert 20 to distribute the aerosol generally evenly throughout the mouth of the smoker during use. Thus, when the aerosol is delivered to the mouth of the smoker, the aerosol can enter the mouth and move in different directions to provide a fuller mouth feel as compared to an electronic smoking article having a single aperture on axis that directs the aerosol to a single location in the mouth of the smoker.

In addition, the outlet 21 and the off-axis channel 23 are arranged such that droplets of non-aerosolized liquid material entrained in the aerosol will encounter the inner surface of the mouth end insert 20 and/or the inner surface of the off-axis channel 23, thereby enabling removal or dispersal of the droplets. In a preferred embodiment, the outlet 21 of the mouth end insert 20 is located at the end of the off-axis channel 23 and is skewed at an angle of 5 to 60 ° relative to the central longitudinal axis of the electronic smoking article 60 to more thoroughly disperse the aerosol throughout the mouth of the smoker and remove droplets during use.

Preferably, each outlet 21 has a diameter of from about 0.015 inches to about 0.090 inches (e.g., from about 0.020 inches to about 0.040 inches, or from about 0.028 inches to about 0.038 inches). If desired, the size of the outlet 21 and the off-axis channels 23, as well as the number of outlets 21, may be selected to adjust the Resistance To Draw (RTD) of the electronic smoking article 60.

Preferably, the electronic smoking article 60 is substantially the same size as a conventional smoking article. In certain embodiments, the electronic smoking article 60 can have a length of about 80 mm to about 110 mm, preferably a length of about 80 mm to about 100 mm, and a diameter of about 7 mm to about 8 mm. For example, in one embodiment, the electronic smoking article is about 84 millimeters in length and about 7.8 millimeters in diameter.

The outer cylindrical housing 22 of the electronic smoking article 60 may be formed of any suitable material or combination of materials. Preferably, the outer cylindrical housing 22 is at least partially formed of metal and is part of an electrical circuit.

In the embodiment shown in fig. 2, at least a portion of the outer cylindrical shell 22 may be resilient to allow a smoker to squeeze the shell 22 and container 14 during smoking to release liquid material from the container 14 and activate the heater 19. Thus, the cylindrical outer housing 22 may be formed from a variety of materials including plastic, rubber, and combinations thereof. In one embodiment, the cylindrical outer housing 22 is formed from silicone rubber. The outer cylindrical shell 22 may be any suitable color and/or may include graphics or other indicia printed thereon.

Preferably, the liquid aerosol formulation used in each of the electronic smoking articles 60 described herein comprises at least one aerosol former, water, a nicotine source, and at least one acidic substance.

In a preferred embodiment, the at least one aerosol former is selected from the group consisting of propylene glycol, glycerin, and combinations thereof. Preferably, the at least one aerosol former is present in an amount ranging from about 40% by weight based on the weight of the liquid formulation to about 90% by weight based on the weight of the liquid formulation (e.g., from about 50% to about 80%, from about 55% to about 75%, or from about 60% to about 70%). Additionally, in one embodiment, the liquid formulation may include propylene glycol and glycerin in a weight ratio of about 3:2.

Preferably, the liquid formulation further comprises water. The water content ranges from about 5% by weight based on the weight of the liquid formulation to about 40% by weight based on the weight of the liquid formulation, more preferably from about 10% by weight based on the weight of the liquid formulation to about 15% by weight based on the weight of the liquid formulation.

The liquid aerosol formulation optionally includes at least one fragrance in an amount ranging from about 0.2% to about 15% (e.g., from about 1% to about 12%, from about 2% to about 10%, or from about 5% to about 8%) by weight. The at least one fragrance may be a natural fragrance or an artificial fragrance. Preferably, the at least one flavoring is selected from the group consisting of tobacco flavors, menthol, wintergreen oil, peppermint, vanilla flavors, fruit flavors, nut flavors, wine flavors, and combinations thereof.

Also preferably, the liquid aerosol formulation comprises an acidic material having a melting point and/or boiling point of at least about 150 ℃. For example, the acidic material can have a melting point and/or boiling point in the range of from about 150 ℃ to about 300 ℃, more preferably from about 150 ℃ to about 250 ℃ (e.g., from about 160 ℃ to about 240 ℃, from about 170 ℃ to about 230 ℃, from about 180 ℃ to about 220 ℃, or from about 190 ℃ to about 210 ℃). By including an acidic substance having a melting point and/or boiling point within this range, the acidic substance can be volatilized when heated by a heating element of an electronic smoking article as described above. In embodiments using heating coils and cores, the heating coils may reach an operating temperature of 300 ℃ or about 300 ℃.

Also preferably, the acidic material is present in the liquid aerosol formulation in an amount sufficient to lower the pH of the liquid aerosol formulation to a range of from about 4 to about 8, more preferably from about 5 to about 7, or from about 5.5 to about 6.5. In addition, the acidic substance preferably can condense at ambient temperature.

Suitable acidic materials for use in liquid aerosol formulations include, but are not limited to, succinic acid, tartaric acid, sulfuric acid, carbonic acid, malonic acid, tartronic acid, levulinic acid, acetic acid, benzoic acid, adipic acid, glutaric acid, pimelic acid, and combinations thereof. Preferably, the acidic species is included in an amount ranging from about 0.1% to about 15% (e.g., from about 1% to about 12%, from about 2% to about 10%, from about 3% to about 9%, or from about 4% to about 8%) by weight.

The amount of the acidic material added to the liquid aerosol formulation can depend on the strength of the acidic material and the amount necessary to adjust the pH of the liquid aerosol formulation to the desired range. If too much acid is added, substantially all of the available nicotine will be protonated and will enter the particulate phase of the aerosol, leaving very little unprotonated nicotine in the gas phase of the aerosol. The aerosol generated may not produce a level of sensory response in terms of throat bitterness sufficient to satisfy the preferences of most ordinary smokers of lit-end cigarettes. Conversely, if too little acid is added, a greater amount of nicotine will remain unprotonated and in the vapor phase of the aerosol, so that the smoker will experience greater throat harshness. Throat harshness may be perceived to levels unpleasant to inhale the aerosol using liquid aerosol formulations having a nicotine content greater than about 2% by weight and without the addition of an acid in accordance with the teachings herein, and levels unpleasant to inhale the aerosol may be perceived using liquid formulations having a nicotine content greater than about 4% by weight and without the addition of an acid in accordance with the teachings herein. With the addition of an acidic substance according to the teachings herein, the perceived throat harshness remains at a desired level, similar to that experienced with a lit-end cigarette.

Preferably, the liquid aerosol formulation further comprises at least one nicotine source. The content of nicotine in the liquid aerosol formulation ranges from about 1% by weight to about 10% by weight (e.g., from about 2% to about 9%, from about 2% to about 8%, from about 2% to about 6%).

In one embodiment, the nicotine source may comprise nicotine in a molecular state (unprotonated). Typically, the molecular nicotine in aqueous solution has a pH of from about 9 to about 10. Thus, it is necessary to add an amount of acidic material sufficient to lower the pH to from about 4 to about 8. In one embodiment, the molecular state (unprotonated) nicotine is added in liquid form.

In an alternative embodiment, the nicotine source may include one or more nicotine salts that may be added to the formulation to provide nicotine and the acidic substance. The nicotine salt can be a salt of succinic acid, tartaric acid, sulfuric acid, carbonic acid, malonic acid, tartronic acid, levulinic acid, acetic acid, benzoic acid, adipic acid, glutaric acid, pimelic acid, and combinations thereof. A preferred nicotine acid salt is nicotine bitartrate.

The liquid aerosol formulation is capable of forming an aerosol having a particulate phase and a gas phase when the liquid aerosol formulation is vaporized in the electronic smoking article. Preferably, the particulate phase comprises a protonated aerosol and the gas phase comprises unprotonated nicotine. It is also preferred that a major amount of nicotine is protonated and in the particulate phase and a minor amount of nicotine is contained in the gas phase. Once the liquid aerosol formulation has evaporated, the vapour condenses, the nicotine is protonated, and particles comprising protonated nicotine are formed. A small amount of nicotine remains unprotonated and in the gas phase of the newly generated aerosol. Preferably, from about 0.1% to about 1.0% of the total nicotine content of the aerosol is considered unprotonated (e.g., from about 0.2% to about 0.7%, or from about 0.3% to about 0.5%) as a result of the addition of the acidic substance, while the remaining available nicotine is considered to be in protonated (charged) form and in the particulate phase. Preferably, the particulate phase comprises particles ranging in size from about 0.2 microns to about 2 microns.

Without wishing to be bound by theory, it is believed that the addition of an acidic substance having a desired melting point and/or boiling point range as taught herein allows the acidic substance to begin entering the initial, incompletely formed aerosol-vapor system as the liquid is vaporized by the heater of the electronic smoking article. The acidic material allows for continued heating and retention of the protonation of nicotine such that a substantial portion, if not substantially all, of the nicotine remains in and/or enters the particulate phase when the aerosol is formed. As with aerosols produced by lit-end cigarettes, the initial gas phase nicotine content of the electronically produced aerosol is very low, preferably in the range of about 0.1 to 1.0% by weight of the total nicotine content of the aerosol, more preferably in the range of about 0.1 to 0.5% by weight of the total nicotine content of the aerosol. Furthermore, nicotine in the particulate phase is significantly protonated and therefore electrically charged, and for the most part cannot enter the gas phase of the aerosol.

In addition, the acidic substance may be selected and its concentration may be set to be sufficient to maintain the above-mentioned, desired low level of nicotine in the gas phase, even in the case of a high content of nicotine in the liquid formulation. Adult smokers of lit-end cigarettes claim that they cannot experience the warmth in the chest cavity they would like to feel by inhaling cigarette smoke when smoking the more common, commercially available electronic smoking articles. These existing electronic smoking articles tend to have tobacco tar formulations with a relatively low content of nicotine (typically about 2% or less). For adult cigarette smokers, these existing electronic smoking articles lack the important, pleasant sensory response of the cigarette smoking experience — feeling chest warmth. While existing electronic smoking devices with tobacco formulations having higher nicotine content (above about 2% by weight, but typically about 3% or 4%) tend to provide more of the expected perceived warmth of the chest, to date, aerosols have produced unacceptably high levels of harshness in the throat. It has been found that the gas phase nicotine content of the aerosol comprises about 3% to 4% of the total nicotine content of the aerosol.

By preparing a liquid formulation containing greater than 2% or more by weight nicotine, more preferably in the range of from 2% to about 6% by weight, and adding an acidic substance in accordance with the teachings herein, the perceived sensory benefits associated with higher nicotine levels (warmth in the chest) are achieved while also avoiding the previously described sensory deficiencies associated with higher nicotine (too bitter in the throat), thereby providing an adult cigarette smoker with an underlying electronic smoking article that can provide a perceptually pleasing smoking experience including a low to mild bitter response in the throat, and the perception of warmth in the chest.

With the improved liquid formulation, a substantial portion of the nicotine in the particulate phase is protonated by the presence of the acidic species, and any nicotine removed from the gas phase by throat absorption is not readily replaced by nicotine from the particulate phase. In contrast, the protonated nicotine remains in the particulate phase and does not allow to increase the bitter response to unacceptable levels. The aerosol produced in accordance with the teachings herein provides a pleasant low to mild sensation of bitterness substantially in the expectations of smokers of lit-end cigarettes, even in the case of liquid formulations with higher nicotine content.

With respect to smoking enjoyment, a pleasant sensation may be experienced in low to moderate throat bitterness, whereas an unpleasant sensation, as well as a potentially unpleasant sensation, may be experienced in high to very high throat bitterness.

To determine the amount of nicotine in the gas phase in each puff, a test electronic smoking article comprising a liquid aerosol formulation as described herein was compared to a control electronic smoking article having a liquid aerosol formulation that did not contain an acidic substance using a gas chromatography/mass spectrometer (GC/MS). A controlled electronic smoking article forms an aerosol using a liquid aerosol formulation comprising 6% nicotine and 94% of a mixture of glycerol and water 4:1 and no acidic material. Test electronic smoking articles aerosol was formed using a liquid aerosol formulation comprising 6% nicotine, 89% of a mixture of glycerol and water 4:1, and 5% levulinic acid. Each electronic smoking article tested over 49 puffs. To determine the amount of nicotine in the gas phase, the gas vapour is collected with the support of Cambridge pad. The test results are shown in fig. 5. As shown, the test electronic smoking article provided less nicotine in the gas phase per puff than the control electronic smoking article.

Surprisingly, as shown in figure 5, the addition of an acidic substance to a liquid aerosol formulation reduces nicotine in the gas phase. While not wishing to be bound by theory, it is believed that the addition of an acidic substance to a liquid aerosol formulation to form a liquid aerosol formulation having a pH in the range of from about 4 to about 8 results in an aerosol comprising a substantial amount of protonated nicotine in the particulate phase and a small amount of unprotonated nicotine remaining in the gas phase of the aerosol.

Advantageously, the addition of tartaric acid (and/or nicotine salts thereof) reduces throat harshness during inhalation and exhalation. It has been found that the use of tartaric acid (and/or nicotine salts thereof) in accordance with the teachings herein provides little or no harshness to the throat upon exhalation, which is a desirable feature for sensory response.

In one embodiment, the liquid aerosol formulation may further include ammonia or an ammonia compound in an amount sufficient to further reduce the pH of the liquid aerosol formulation by about 1 to 2 pH units. The addition of ammonia or an ammonia compound prevents or reduces the formation of scorching at the heater without affecting the harshness in the throat or warmth in the chest.

When the term "about" is used in this specification in connection with a numerical value, it is intended that the associated numerical value include a tolerance of ± 10% around the stated numerical value. In addition, when percentages are mentioned in the present specification, it is intended that these percentages are based on weight, i.e. as weight percentages. The term "up to" includes all numerical quantities from zero to the stated upper limit and between. When ranges are stated, the ranges include all values therebetween, for example, increments of 0.1%.

Additionally, the terms "substantially" and "substantially," when used in conjunction with geometric shapes, are intended to indicate that the degree of precision of the geometric shapes is not a requirement, but rather that the limits of the shapes are within the scope of the disclosure. Although the tubular elements in the embodiments are preferably cylindrical, other tube cross-sectional forms are also contemplated, such as square, rectangular, oval, triangular, and other shapes. When geometric terms are used, "substantially" and "essentially" are intended to include not only features that meet the strict rules, but also features that are fairly close to the strict rules.

It will now be apparent that the present specification describes new and improved nonobvious electronic smoking devices, liquid aerosol formulations, and methods in sufficient detail to enable those of ordinary skill in the art to understand. In addition, it will be apparent to those skilled in the art that there are numerous modifications, variations, substitutions and equivalents to the features of the electronic smoking article, the liquid aerosol formulation and the method that do not materially depart from the spirit and scope of the invention. It is therefore expressly intended that all such modifications, variations, substitutions and equivalents which fall within the spirit and scope of the present invention as defined by the appended claims be embraced thereby.

Claims

1. A liquid aerosol formulation comprising:

an aerosol former;

water in an amount of from 0.1% to about 40% by weight based on the weight of the liquid aerosol formulation;

nicotine bitartrate in an amount sufficient to produce 2% to 10% nicotine by weight based on the weight of the liquid aerosol formulation; and

an acidic species capable of condensing at ambient temperatures, the acidic species having a boiling point of at least 150 ℃, the acidic species being present in an amount ranging from about 0.1% to about 15% by weight based on the weight of the liquid aerosol formulation,

the acidic material comprises one of succinic acid, tartaric acid, sulfuric acid, carbonic acid, malonic acid, tartronic acid, acetic acid, benzoic acid, adipic acid, glutaric acid, pimelic acid, subcombinations thereof, or combinations thereof,

the liquid aerosol formulation has a pH value in the range from about 4 to about 8;

wherein the liquid aerosol formulation is a mixture comprising the aerosol former, water, nicotine bitartrate and an acidic substance,

wherein the liquid aerosol formulation forms an aerosol having a particulate phase and a gas phase when heated,

the particulate phase comprises protonated nicotine, and

the gas phase comprises non-protonated nicotine and,

the content of gas phase nicotine in the aerosol is equal to or less than about 1% of the total content of nicotine in the aerosol.

2. The liquid aerosol formulation of claim 1, further comprising:

at least one fragrance in an amount ranging from about 0.2% to about 15% by weight.

3. The liquid aerosol formulation of claim 1, wherein the aerosol former comprises one of propylene glycol, glycerin, a sub-combination thereof, or a combination thereof.

4. The liquid aerosol formulation of claim 3, wherein the aerosol former is present in an amount ranging from about 40% to about 90% by weight.

5. The liquid aerosol formulation of claim 3, wherein the liquid aerosol formulation comprises glycerin and propylene glycol in a ratio of about 2:3 or greater.

6. The liquid aerosol formulation of claim 1, wherein the particulate phase comprises particles ranging in size from about 0.2 microns to about 2 microns.

7. The liquid aerosol formulation of claim 1, wherein the acidic substance comprises one of succinic acid, sulfuric acid, carbonic acid, tartronic acid, acetic acid, benzoic acid, adipic acid, glutaric acid, pimelic acid, subcombinations thereof, or combinations thereof.

8. The liquid aerosol formulation of claim 1, wherein the acidic material comprises tartaric acid.

9. The liquid aerosol formulation of claim 1, further comprising ammonia or an ammonia-containing compound in an amount sufficient to lower the pH of the liquid aerosol formulation by about 1 to about 2 pH units.

10. The liquid aerosol formulation of claim 1, wherein the water is present in an amount ranging from about 5% to about 40% by weight based on the weight of the liquid aerosol formulation.

11. The liquid aerosol formulation of claim 1, wherein the water is present in an amount ranging from about 5% to about 15% by weight based on the weight of the liquid aerosol formulation.

12. The liquid aerosol formulation of claim 1, wherein the liquid aerosol formulation has a pH in a range from about 5.5 to about 8.

13. An electronic smoking article comprising:

a heater; and

a liquid aerosol formulation according to claim 1;

wherein the heater is operative to volatilize the liquid aerosol formulation and form an aerosol.

14. The electronic smoking article of claim 13, further comprising:

a container containing the liquid aerosol formulation;

wherein the heater comprises a capillary tube in fluid communication with the reservoir.

15. The electronic smoking article of claim 14, wherein the container includes a valve at an outlet of the container.

16. The electronic smoking article of claim 14, wherein the container is compressible.

17. The electronic smoking article of claim 13, further comprising:

a filamentous core; and

a container;

wherein the heater is a heating coil in communication with the filamentary wick, and

the filamentary wick draws the liquid aerosol formulation from the container by capillary action.

18. The electronic smoking article of claim 17, further comprising:

an outer tube extending in a longitudinal direction; and

an inner tube positioned within the outer tube;

wherein the heating coil is located in the inner tube,

the filamentary wick is in communication with the container and surrounded by the heating coil.

19. The electronic smoking article of claim 13, wherein the acidic substance comprises one of succinic acid, sulfuric acid, carbonic acid, tartronic acid, acetic acid, benzoic acid, adipic acid, glutaric acid, pimelic acid, subcombinations thereof, or combinations thereof.

20. The electronic smoking article of claim 13, wherein the acidic substance comprises tartaric acid.

21. A method of forming an aerosol by an electronic smoking article, the method comprising:

heating a liquid aerosol formulation to a temperature sufficient to form an aerosol, the liquid aerosol formulation comprising:

an aerosol former;

an acidic species in an amount ranging from about 0.1% to about 15% by weight based on the weight of the liquid aerosol formulation, the liquid aerosol formulation having a pH in a range from about 4 to about 8, the acidic species being condensable at ambient temperature, the acidic species having a boiling point of at least 150 ℃,

the acidic material comprises one of succinic acid, tartaric acid, sulfuric acid, carbonic acid, malonic acid, tartronic acid, acetic acid, benzoic acid, adipic acid, glutaric acid, pimelic acid, subcombinations thereof, or combinations thereof; wherein the liquid aerosol formulation is a mixture comprising the aerosol former, water, nicotine bitartrate and an acidic substance,

wherein, during operation of the electronic smoking article, the liquid aerosol formulation is capable of forming, when heated, an aerosol having a particulate phase and a gas phase, the gas phase of the aerosol having a nicotine content equal to or less than about 1% of the total nicotine content of the aerosol.

22. The method of claim 21, wherein the acidic substance comprises tartaric acid in an amount ranging from about 0.1% to about 15% by weight based on the weight of the liquid aerosol formulation.

23. The method of claim 21, wherein the liquid aerosol formulation further comprises ammonia or an ammonia-containing compound in an amount sufficient to reduce the pH of the liquid aerosol formulation by about 1 to about 2 pH units.

24. A method of forming a component of an electronic smoking article, the method comprising:

the liquid aerosol formulation is prepared by mixing an aerosol former, nicotine bitartrate, water and an acidic substance to obtain a mixture of liquid aerosol formulations,

the aerosol former is present in an amount of at least about 50%, the water is present in an amount of from 0.1% to about 40%,

the acidic substance being capable of condensing at ambient temperature, the acidic substance having a boiling point of at least 150 ℃,

the acidic species is present in an amount ranging from about 0.1% to about 15% by weight based on the weight of the liquid aerosol formulation,

the liquid aerosol formulation has a pH in the range from about 4 to about 8,

the amount of nicotine bitartrate added to the liquid aerosol formulation is sufficient to produce 2% to 10% nicotine by weight based on the weight of the liquid aerosol formulation,

the content of gas phase nicotine in the aerosol is equal to or less than about 1% of the total content of nicotine in the aerosol; and

filling a container of a component of an electronic smoking article with the liquid aerosol formulation.

25. The method of claim 24, wherein the acidic material comprises one of succinic acid, sulfuric acid, carbonic acid, tartronic acid, acetic acid, benzoic acid, adipic acid, glutaric acid, pimelic acid, subcombinations thereof, or combinations thereof.

26. The method of claim 24, wherein the acidic material comprises tartaric acid.

27. A liquid formulation for an electronic smoking article, the liquid formulation comprising:

an aerosol former;

water in an amount of from 0.1% to about 40% by weight based on the weight of the liquid formulation;

a nicotine salt in an amount sufficient to produce 2% to 10% nicotine by weight based on the weight of the liquid formulation; and

benzoic acid in an amount ranging from about 2.0% to about 8.0% by weight;

wherein the liquid formulation is a mixture comprising the aerosol former, water, nicotine salt and benzoic acid.

28. The liquid formulation of claim 27,

the amount of nicotine salt ranges from about 2% to about 6% by weight,

the liquid formulation has a pH in the range of from about 4 to about 8,

the liquid aerosol formulation forms an aerosol having a particulate phase and a gas phase when heated,

the particulate phase comprises protonated nicotine and the particulate phase comprises protonated nicotine,

the gas phase comprises non-protonated nicotine and,

29. The liquid formulation of claim 28,

the aerosol former includes glycerin and propylene glycol.

30. The liquid formulation of claim 29,

the nicotine salt includes nicotine bitartrate.

31. The liquid formulation of claim 29,

the aerosol former includes glycerin and propylene glycol in a ratio of about 2:3.

32. The liquid formulation of claim 27,

the nicotine salt includes nicotine bitartrate.